Even though the planet is warming, the sea ice around Antarctica is expanding in the winter. This paradox has stumped scientists, who have struggled to understand why the ice is growing there while ice at the other pole is rapidly melting. In fact, ice in the Antarctic reached an all-time high in 2010 despite that year being one of the hottest ever. Now, scientists have unlocked the mystery, and it all comes back to global warming.
According to a new study published in Nature Geoscience, every year the edges of the Antarctic thaw, sending more and more melting ice out into the ocean. That melted water forms large cold-water plumes in the ocean, which, according to the study, “shields the surface ocean from the warmer deeper waters that are melting the ice shelves.” As temperatures drop in the winter, these cold-water plumes refreeze, adding to the ice in the Antarctic.
The study cautions that while the ice formation in the Antarctic seems to be increasing, the overall melt across the planet is still contributing to a rise in sea level overall. Additionally, the ice below the surface in the Antarctic is still melting as quickly as ever. Recent studies also indicate that while the ice may be increasing on one side, the other side of the Antarctic is decreasing, leading to a reduction in total mass overall.
The Antarctic is losing about 250 billion tons of ice a year, which alone contributes to a rise of .003 inches in sea level, and the loss seems to be moving faster. This effect is exacerbated by the fact that snowfall in the region has been less than expected. Meanwhile, another study shows that strong wind may be contributing to the ice formation. According to Paul Holland, the shift in wind current brought on by climate change has forced the cold water out onto the ocean, which then refreezes, contributing to the ice mass. Regardless of the method, it is apparent that global warming is contributing to the changing Antarctic.
Images from Christopher